Capacitive communication system and Bluetooth pairing method

ABSTRACT

There is provided a capacitive communication system including an object and a capacitive touch panel. The object includes a plurality of induction conductors configured to have different potential distributions at different time intervals by modulating respective potentials thereof. The capacitive touch panel includes a plurality of sensing electrodes configured to form a coupling electric field with the induction conductors to detect the different potential distributions at the different time intervals. When the different potential distributions match a predetermined agreement between the object and the capacitive touch panel, a near field communication is formed between the object and the capacitive touch panel.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part application of U.S.application Ser. No. 14/565,622, filed Dec. 10, 2014, the fulldisclosure of which is incorporated herein by reference.

BACKGROUND

1. Field of the Disclosure

This disclosure generally relates to an interactive input device and,more particularly, to a capacitive touch device, a capacitivecommunication device and a communication system.

2. Description of the Related Art

Capacitive sensors generally include a pair of electrodes configured tosense a finger. When a finger is present, the amount of chargetransferring between the pair of electrodes can be changed so that it isable to detect whether the finger is present or not according to avoltage variation. It is able to form a sensing matrix by arranging aplurality of electrode pairs in matrix.

FIGS. 1A and 1B are schematic diagrams of a conventional capacitivesensor which includes a first electrode 91, a second electrode 92, adrive circuit 93 and a detection circuit 94. The drive circuit 93 isconfigured to input a drive signal to the first electrode 91. Electricfield can be formed between the first electrode 91 and the secondelectrode 92 so as to transfer charges to the second electrode 92. Thedetection circuit 94 is configured to detect the amount of chargestransferred to the second electrode 92.

When a finger is present, e.g. shown by an equivalent circuit 8, thefinger may disturb the electric field between the first electrode 91 andthe second electrode 92 so that the amount of transferred charges isreduced. The detection circuit 94 can detect a voltage variation toaccordingly identify the presence of the finger.

In addition, when another capacitive sensor approaches, the electricfield between the first electrode 91 and the second electrode 92 is alsochanged thereby changing the amount of transferred charges. Thedetection circuit 94 is also able to detect a voltage variation toaccordingly identify the presence of said another capacitive sensor.

SUMMARY

Accordingly, the present disclosure provides a capacitive touch device,a capacitive communication device and a communication system capable ofdetecting the touch event as well as performing the near fieldcommunication.

The present disclosure provides a capacitive touch device, a capacitivecommunication device and a communication system that may identify thetouch event according to the variation of a norm of vector of twodetection components and perform the near field communication accordingto the phase variation of detection signals.

The present disclosure further provides a capacitive touch device, acapacitive communication device and a communication system that have alonger transmission distance.

The present disclosure further provides a capacitive communicationsystem which identifies different objects and communicates data with theobjects using the near field communication.

The present disclosure further provides a Bluetooth pairing method whichhas a simplified triggering procedure.

The present disclosure provides a capacitive communication systemincluding an object and a capacitive touch panel. The object includes atleast one induction conductor and a controller. The controller iscoupled to the at least one induction conductor and configured tomodulate a potential of the at least one induction conductor to beconfigured as identification data. The capacitive touch panel includesat least one sensing electrode and a processing unit. The at least onesensing electrode is configured to form a coupling electric field withthe at least one induction conductor, wherein the sensing electrode isconfigured to output a detection signal corresponding to theidentification data according to the coupling electric field. Theprocessing unit is configured to identify whether the object is aspecific object according to the detection signal.

The present disclosure further provides a Bluetooth pairing methodadapted to a Bluetooth pairing procedure between a master deviceincluding a capacitive touch panel and a slave device including at leastone induction conductor. The Bluetooth pairing method includes the stepsof: detecting, by the capacitive touch panel, the at least one inductionconductor; identifying, by the master device, an arrangementcharacteristic of the at least one induction conductor when thecapacitive touch panel senses the at least one induction conductor; andperforming the Bluetooth pairing procedure when the master deviceidentifies the arrangement characteristic matching a predeterminedagreement.

The present disclosure further provides a capacitive communicationsystem including an object and a capacitive touch panel. The objectincludes a plurality of induction conductors configured to havedifferent potential distributions at different time intervals bymodulating respective potentials on the induction conductors. Thecapacitive touch panel includes a plurality of sensing electrodesconfigured to form a coupling electric field with the inductionconductors to detect the different potential distributions at thedifferent time intervals, wherein when the differential potentialdistributions match a predetermined agreement, a near fieldcommunication between the capacitive touch panel and the object isformed.

In the capacitive touch device, capacitive communication device andcommunication system according to some embodiments of the presentdisclosure, the phase-modulated drive signal may be a phase-shift keying(PSK) signal or a differential phase shift keying (DPSK) signal. The PSKsignal may be a biphase shift keying (BPSK) signal, a quadrature phaseshift keying (QPSK) signal, an 8-PSK signal or a 16-PSK signal. The DPSKsignal may be a differential BPSK (DBPSK) signal, a differential QPSK(DQPSK) signal, a differential 8PSK (D-8PSK) signal or a differential16PSK (D-16PSK) signal.

In the present disclosure, the capacitive touch panel is aself-capacitive touch panel or a mutual-capacitive touch panel.

In the present disclosure, the object is, for example, an electroniclock, a mouse device, an earphone, a watch, a bracelet, a smart pen, adoll or an electronic mobile device having another capacitive touchpanel.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, advantages, and novel features of the present disclosurewill become more apparent from the following detailed description whentaken in conjunction with the accompanying drawings.

FIGS. 1A-1B are schematic block diagrams of the conventional capacitivesensor.

FIG. 2 is a schematic diagram of the capacitive touch sensing deviceaccording to one embodiment of the present disclosure.

FIGS. 3A-3B are other schematic diagrams of the capacitive touch sensingdevice according to some embodiments of the present disclosure.

FIG. 4 is a schematic diagram of the norm of vector and the thresholdused in the capacitive touch sensing device according to one embodimentof the present disclosure.

FIG. 5 is a schematic diagram of the capacitive touch sensing deviceaccording to another embodiment of the present disclosure.

FIG. 6 is a flow chart of the operation of the capacitive touch sensingdevice shown in FIG. 5.

FIG. 7 is a schematic block diagram of a communication system accordingto one embodiment of the present disclosure.

FIG. 7A is a schematic diagram of the QPSK modulation.

FIG. 8 is another schematic block diagram of a communication systemaccording to one embodiment of the present disclosure.

FIG. 9 is an operational schematic diagram of a communication systemaccording to one embodiment of the present disclosure.

FIG. 10 is an operation sequence diagram of a communication systemaccording to one embodiment of the present disclosure.

FIGS. 11A-11C are schematic diagrams of the electric field between adrive electrode and a receiving electrode.

FIG. 12 is a flow chart of a communication method of a communicationsystem according to one embodiment of the present disclosure.

FIG. 13 is a block diagram of a capacitive communication systemaccording to an alternative embodiment of the present disclosure.

FIG. 14 is a schematic diagram of a capacitive communication systemaccording to an alternative embodiment of the present disclosure.

FIG. 15A is a schematic diagram of identification data according to analternative embodiment of the present disclosure.

FIG. 15B is a schematic diagram of transmission data according to analternative embodiment of the present disclosure.

FIG. 16 is a schematic diagram of an object and induction conductorsaccording to an alternative embodiment of the present disclosure.

FIG. 17 is an operational schematic diagram of the object in FIG. 16.

FIG. 18 is schematic diagram of controlling the potential of inductionconductors in an alternative embodiment of the present disclosure.

FIG. 19 is a block diagram of Bluetooth pairing according to analternative embodiment of the present disclosure.

FIGS. 20-21 are flow charts of Bluetooth pairing methods according toalternative embodiments of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENT

It should be noted that, wherever possible, the same reference numberswill be used throughout the drawings to refer to the same or like parts.

Referring to FIG. 2, it shows a schematic diagram of the capacitivetouch sensing device according to an embodiment of the presentdisclosure. The capacitive touch sensing device of this embodimentincludes a sensing element 10, a drive unit 12, a detection circuit 13and a processing unit 14. The capacitive touch sensing device isconfigured to detect whether an object (e.g. a finger or a metal plate,but not limited to) approaches the sensing element 10 according to thechange of the amount of charges on the sensing element 10.

The sensing element 10 includes a first electrode 101 (e.g. a driveelectrode) and a second electrode 102 (e.g. a receiving electrode), andelectric field can be produced to form a coupling capacitance 103between the first electrode 101 and the second electrode 102 when avoltage signal is inputted to the first electrode 101. The firstelectrode 101 and the second electrode 102 may be arranged properlywithout any limitation as long as the coupling capacitance 103 can beformed (e.g. via a dielectric layer), wherein principles of forming theelectric field and the coupling capacitance 103 between the firstelectrode 101 and the second electrode 102 is well known and thus arenot described herein. The present disclosure is to eliminate theinterference on detecting results due to the phase shift caused by thecapacitance on signal lines.

The drive unit 12 may be a signal generator and configured to input adrive signal x(t) to the first electrode 101 of the sensing element 10.The drive signal x(t) may be a time-varying signal, such as a periodicsignal. In other embodiments, the drive signal x(t) may be a meandersignal (e.g. a sinusoidal signal) or a pulse signal (e.g. a squarewave), but not limited thereto. The drive signal x(t) may couple adetection signal y(t) on the second electrode 102 through the couplingcapacitance 103.

The detection circuit 13 is coupled to the second electrode 102 of thesensing element 10 and configured to detect the detection signal y(t)and to modulate the detection signal y(t) respectively with two signalsso as to generate a pair of modulated detection signals, which areserved as two components I and Q of a two-dimensional detection vector.The two signals may be continuous signals or vectors that are orthogonalor non-orthogonal to each other. In one aspect, the two signals includea sine signal and a cosine signal, i.e. the two signals preferably havedifferent phases.

The processing unit 14 is configured to calculate an amplitude of thepair of the modulated detection signals, which is served as a norm ofvector of the two-dimensional detection vector (I,Q), and to compare thenorm of vector with a threshold TH so as to identify a touch event. Inone aspect, the processing unit 14 may calculate the norm of vectorR=√{square root over (I²+Q²)} by using software. In other aspect, theprocessing unit 14 may calculate by hardware or firmware, such as usingthe CORDIC (coordinate rotation digital computer) shown in FIG. 4 tocalculate the norm of vector R=√{square root over (i²+q²)}, wherein theCORDIC is a well known fast algorithm. For example, when there is noobject closing to the sensing element 10, the norm of vector calculatedby the processing unit 14 is assumed to be R; and when an object ispresent nearby the sensing element 10, the norm of vector is decreasedto R′. When the norm of vector R′ is smaller than the threshold TH, theprocessing unit 14 may identify that the object is present close to thesensing element 10 and induces a touch event. It should be mentionedthat when another object, such as a metal plate, approaches the sensingelement 10, the norm of vector R may be increased. Therefore, theprocessing unit 14 may identify a touch event occurring when the norm ofvector becomes larger than a predetermined threshold.

In another embodiment, the processing unit 14 may perform coding on thetwo components I and Q of the two-dimensional detection vector by usingquadrature amplitude-shift keying (QASK), such as 16-QASK. A part of thecodes may be corresponded to the touch event and the other part of thecodes may be corresponded to non-touch state and these codes arepreviously saved in the processing unit 14. When the processing unit 14calculates the QASK code of two current components I and Q according tothe pair of the modulated detection signals, it is able to identify thatwhether an object is present near the sensing element 10.

FIGS. 3A and 3B respectively show another schematic diagram of thecapacitive touch sensing device according to an embodiment of thepresent disclosure in which embodiments of the detection circuit 13 areshown.

In FIG. 3A, the detection circuit 13 includes two multipliers 131 and131′, two integrators 132 and 132′, an analog-to-digital converter (ADC)133, and is configured to process the detection signal y(t) so as togenerate a two-dimensional detection vector (I,Q). The ADC converter 133is configured to digitize the detection signal y(t) to generate adigitized detection signal y_(d)(t). The two multipliers 131 and 131′are indicated to modulate two signals S₁ and S₂ with the digitizeddetection signal y_(d)(t) so as to generate a pair of modulateddetection signals y₁(t) and y₂(t). In order to sample the pair ofmodulated detection signals y₁(t) and y₂(t), two integrators 132 and132′ are configured to integrate the pair of modulated detection signalsy₁(t) and y₂(t) so as to generate two digital components I and Q of thetwo-dimensional detection vector (I,Q). In this embodiment, the twointegrators 132 and 132′ may be any proper integration circuit, such asthe capacitor.

In FIG. 3B, the detection circuit 13 includes two multipliers 131 and131′, two integrators 132 and 132′, two analog-to-digital converters(ADC) 133 and 133′ configured to process the detection signal y(t) so asto generate a two-dimensional detection vector (I,Q). The twomultipliers 131 and 131′ are indicated to modulate two signals, such asS₁=√{square root over (2/T)} cos(ωt) and S₂=√{square root over (2/T)}sin(ωt) herein, with the detection signal y(t) so as to generate a pairof modulated detection signals y₁(t) and y₂(t). In order to sample thepair of modulated detection signals y₁(t) and y₂(t), two integrators 132and 132′ are configured to integrate the pair of modulated detectionsignals y₁(t) and y₂(t). In this embodiment, the two integrators 132 and132′ may be any proper integration circuit, such as the capacitor. Thetwo ADC 133 and 133′ are configured to digitize the pair of modulateddetection signals y₁(t) and y₂(t) being integrated so as to generate twodigital components I and Q of the two-dimensional detection vector(I,Q). It is appreciated that the two ADC 133 and 133′ start to acquiredigital data when voltages on the two integrators 132 and 132′ arestable.

In addition to the two continuous signals mentioned above may be used asthe two signals, the two signals may also be two vectors, for exampleS₁=[1 0 −1 0] and S₂[0 −1 0 1] so as to simplify the circuit structure.The two signals may be proper simplified vectors without any limitationas long as the used vectors may simplify the processes of modulation anddemodulation.

As mentioned above, the detection method of the capacitive touch sensingdevice of the present disclosure includes the steps of: inputting adrive signal to a first electrode of a sensing element; modulating adetection signal coupled to a second electrode from the drive signalthrough a coupling capacitance respectively with two signals so as togenerate a pair of modulated detection signals; and calculating a scaleof the pair of modulated detection signals to accordingly identify atouch event.

Referring to FIG. 3A for example, the drive unit 12 inputs a drivesignal x(t) to the first electrode 101 of the sensing element 10, andthe drive signal x(t) may couple a detection signal y(t) on the secondelectrode 102 of the sensing element 10 through the coupling capacitance103. Next, the ADC 133 digitizes the detection signal y(t) to generate adigitized detection signal y_(d)(t). The detection circuit 13respectively modulates the detection signal y(t) with two signals S₁ andS₂ to generate a pair of modulated detection signals y₁(t) and y₂(t),wherein the two signals may be two vectors S₁=[1 0 −1 0] and S₂=[0 −1 01] herein. The processing unit 14 calculates a scale of the pair ofmodulated detection signals y₁(t) and y₂(t) to accordingly identify atouch event, wherein the method of calculating the scale of the pair ofmodulated detection signals y₁(t) and y₂(t) may be referred to FIG. 4and its corresponding descriptions. In addition, before calculating thescale of the pair of modulated detection signals y₁(t) and y₂(t), theintegrator 132 and/or 132′ may be used to integrate the pair ofmodulated detection signals y₁(t) and y₂(t) and then output the twodigital components I and Q of the two-dimensional detection vector(I,Q).

Referring to FIG. 3B for example, the drive unit 12 inputs a drivesignal x(t) to the first electrode 101 of the sensing element 10, andthe drive signal x(t) may couple a detection signal y(t) on the secondelectrode 102 of the sensing element 10 through the coupling capacitance103. Next, the detection circuit 13 respectively modulates the detectionsignal y(t) with two signals S₁ and S₂ to generate a pair of modulateddetection signals y₁(t) and y₂(t). The processing unit 14 calculates ascale of the pair of modulated detection signals y₁(t) and y₂(t) toaccordingly identify a touch event, wherein the method of calculatingthe scale of the pair of modulated detection signals y₁(t) and y₂(t) maybe referred to FIG. 4 and its corresponding descriptions. In addition,before calculating the scale of the pair of modulated detection signalsy₁(t) and y₂(t), the integrator 132 and/or 132′ may be used to integratethe pair of modulated detection signals y₁(t) and y₂(t) and then the ADC133 and/or 133′ may be used perform the digitization so as to output thetwo digital components I and Q of the two-dimensional detection vector(I,Q).

Referring to FIG. 5, it shows a schematic diagram according to anotherembodiment of the present disclosure. A plurality of sensing elements 10arranged in matrix may form a capacitive sensing matrix in which everyrow of the sensing elements 10 is driven by one of the drive units 12₁-12 _(n) and the detection circuit 13 detects output signals of everycolumn of the sensing elements 10 through one of the switch devicesSW₁-SW_(m). As shown in FIG. 5, the drive unit 12 ₁ is configured todrive the first row of sensing elements 10 ₁₁-10 _(1m); the drive unit12 ₂ is configured to drive the second row of sensing elements 10 ₂₁-10_(2m); . . . ; and the drive unit 12 _(n) is configured to drive the nthrow of sensing elements 10 _(n1)-10 _(nm); wherein, n and m are positiveintegers and the value thereof may be determined according to the sizeand resolution of the capacitive sensing matrix without any limitation.

In this embodiment, each of the sensing elements 10 (shown by circlesherein) include a first electrode and a second electrode configured toform a coupling capacitance therebetween as shown in FIGS. 2, 3A and 3B.The drive units 12 ₁-12 _(n) are respectively coupled to the firstelectrode of a row of the sensing elements 10. A timing controller 11 isconfigured to control the drive units 12 ₁-12 _(n) to sequentiallyoutput a drive signal x(t) to the first electrode of the sensingelements 10.

The detection circuit 13 is coupled to the second electrode of a columnof the sensing elements 10 through a plurality of switch devicesSW₁-SW_(m) to sequentially detect a detection signal y(t) coupled to thesecond electrode from the drive signal x(t) through the couplingcapacitance of the sensing elements 10. The detection circuit 13utilizes two signals to respectively modulate the detection signal y(t)to generate a pair of modulated detection signals, wherein details ofgenerating the pair of modulated detection signals has been described inFIGS. 3A, 3B and their corresponding descriptions and thus are notrepeated herein.

The processing unit 14 identifies a touch event and a touch positionaccording to the pair of modulated detection signals. As mentionedabove, the processing unit 14 may calculate a norm of vector of atwo-dimensional detection vector of the pair of modulated detectionsignals and identifies the touch event when the norm of vector is largerthan or equal to, or smaller than or equal to a threshold TH as shown inFIG. 4.

In this embodiment, when the timing controller 11 controls the driveunit 12 ₁ to output the drive signal x(t) to the first row of thesensing elements 10 ₁₁-10 _(1m), the switch devices SW₁-SW_(m) aresequentially turned on such that the detection circuit 13 may detect thedetection signal y(t) sequentially outputted by each sensing element ofthe first row of the sensing elements 10 ₁₁-10 _(1m). Next, the timingcontroller 11 sequentially controls other drive units 12 ₂-12 _(n) tooutput the drive signal x(t) to every row of the sensing elements. Whenthe detection circuit 13 detects all of the sensing elements once, ascan period is accomplished. The processing unit 14 identifies theposition of the sensing elements that the touch event occurs as thetouch position. It is appreciated that said touch position may beoccurred on more than one sensing elements 10 and the processing unit 14may take all positions of a plurality of sensing elements 10 as touchpositions or take one of the positions (e.g. the center or gravitycenter) of a plurality of sensing elements 10 as the touch position.

Referring to FIG. 6, it shows a flow chart of the operation of thecapacitive sensing device shown in FIG. 5, which includes the steps of:inputting a drive signal to a sensing element of a capacitive sensingmatrix (Step S₃₁); digitizing a detection signal outputted by thesensing element (Step S₃₂); respectively modulating the digitizeddetection signal with two signals so as to generate a pair of modulateddetection signals (Step S₃₃); integrating the pair of modulateddetection signals (Step S₃₄); and identifying a touch event and a touchposition (Step S₃₅). Details of the operation of this embodiment havebeen described in FIG. 5 and its corresponding descriptions and thus arenot repeated herein.

In another aspect, in order to save the power consumption of thecapacitive touch sensing device shown in FIG. 5, the timing controller11 may control more than one drive units 12 ₁-12 _(n) to simultaneouslyoutput the drive signal x(t) to the associated row of the sensingelements. The detection unit 13 respectively modulates the detectionsignal y(t) of each row with different two continuous signals S₁ and S₂for distinguishing. In addition, the method of identifying the touchevent and the touch position are similar to FIG. 5 and thus detailsthereof are not repeated herein.

In the embodiment of the present disclosure, the detection circuit 13may further include the filter and/or the amplifier to improve thesignal quality. In addition, the processing unit 14 may be integratedwith the detection circuit 13.

In the above embodiments, as the phase variation of transmitting signalsdue to the signal line does not influence the norm of vector of twodetection components I, Q of the detection signal y(t), i.e. the abovedigital components, the influence of the phase difference due to thesignal line is eliminated by modulating the detection signal y(t) withtwo signals in the receiving end. Similarly, if the drive signal itselfor the inductive signal from an external device have phase variations,as mentioned above the phase variations in the drive signal or theexternal inductive signal do not influence the norm of vector of the twodetection components of the detection signal so that the identificationof the touch event is not affected. Accordingly, in the presentdisclosure a near field communication is performed based on the phasemodulation so as to implement the capacitive touch device, thecapacitive communication device and the communication system have bothfunctions of the touch identification and the near field communication.

Referring to FIG. 7, it is a schematic diagram of a communication systemaccording to one embodiment of the present disclosure, which includes afirst capacitive touch device 400 and a second capacitive touch device500. In one embodiment, the first capacitive touch device 400 and thesecond capacitive touch device 500 are respectively applied to aportable electronic device such as a smart phone, a smart watch, atablet computer, a personal digital assistance or the like, or appliedto a wearable electronic device, and configured to perform a near fieldcommunication through the induced electric field coupled between twodevices. In another embodiment, one of the first capacitive touch device400 and the second capacitive touch device 500 is applied to a portableelectronic device or a wearable electronic device, and the other one isapplied to a home appliance, a security system, an automatic system, avehicle electronic device or the like, and configured to access relativeinformation of the electronic device or perform a relative control.

The first capacitive touch device 400 includes a touch panel 40, aplurality of drive circuits 42 (only one being shown forsimplification), a detection circuit 43 and a processing unit 44. Thesecond capacitive touch device 500 includes a touch panel 50, aplurality of drive circuits 52 (only one being shown forsimplification), a detection circuit 53 and a processing unit 54. Inthis embodiment, a near field communication is implemented through thecoupling electric field Ec between the touch panel 40 and the touchpanel 50. In other words, the touch panel 50 is an external touch panelwith respect to the first capacitive touch device 400, and the touchpanel 40 is an external touch panel with respect to the secondcapacitive touch device 500.

The touch panel 40 includes a plurality of drive electrodes Ed and aplurality of receiving electrodes Er (referring to FIG. 8 for example).As mentioned above, the drive electrodes Ed and the receiving electrodesEr form sensing elements 410 therebetween so as to detect an approachingconductor. As shown in FIG. 8, a touch sensing area 401 of the touchpanel 40 includes a plurality of sensing elements 410. When an externaltouch panel (e.g. the touch panel 50 herein) approaches, the driveelectrodes Ed and the receiving electrodes Er further form a couplingelectric field Ec with the external touch panel. More specifically, thedrive electrodes Ed of the touch panel 40 is configured to form thecoupling electric field Ec with at least one receiving electrode of theexternal touch panel, or the receiving electrodes Er of the touch panel40 is configured to form the coupling electric field Ec with at leastone drive electrode of the external touch panel depending on thefunction of the touch panel 40, e.g. a transmitting end, a receiving endor a transceiver. Similarly, the touch panel 50 includes a plurality ofdrive electrodes Ed and a plurality of receiving electrodes Erconfigured to form a coupling electric field Ec with an external touchpanel (e.g. the touch panel 40 herein). As shown in FIG. 8, a touchsensing area 501 of the touch panel 50 includes a plurality of sensingelements 510. It is appreciated that the touch sensing area 401 and thetouch sensing area 501 may or may not have identical resolution.

The drive circuits 42 are respectively coupled to the drive electrodesEd (referring to FIG. 5 for example) of the touch panel 40 andrespectively include a drive unit 421 and a phase modulation unit 422.The drive unit 421 outputs a phase-fixed drive signal x(t) ortransmission data Data1, wherein the phase-fixed drive signal x(t) maybe the drive signal in a touch detection mode, and the transmission dataData1 is for being sent to an external touch panel in a near fieldcommunication mode. The phase-fixed drive signal x(t) may be acontinuous or non-continuous signal such as a square wave, sinusoidalwave, triangular wave, trapezoidal wave without particular limitations.In one embodiment, the drive circuits 42 are respectively coupled to thedrive electrodes Ed through, for example, a plurality of switchingelements (not shown).

The phase modulation unit 422 includes an encoding unit 4221 and amodulation unit 4222. The encoding unit 4221 is configured to encode thetransmission data Data1, and the modulation unit 4222 is configured tophase-modulate the encoded transmission data and output thephase-modulated drive signal X₁(t)=r₁∠θ₁. In one embodiment, thephase-modulated drive signal X₁(t) may be a phase-shift keying (PSK)signal, wherein the PSK signal may be a biphase shift keying (BPSK)signal, a quadrature phase shift keying (QPSK) signal, an 8-PSK signalor a 16-PSK signal, but not limited thereto. In another embodiment, thephase-modulated drive signal X₁(t) may be a differential phase shiftkeying (DPSK) signal, wherein the DPSK signal may be a differential BPSK(DBPSK) signal, a differential QPSK (DQPSK) signal, a differential 8PSK(D-8PSK) signal or a differential 16PSK (D-16PSK) signal, but notlimited thereto.

Similarly, the drive circuits 52 are respectively coupled to the driveelectrodes Ed of the touch panel 50. The drive circuits 52 include adrive unit 521 configured to output a phase-fixed drive signal x(t) ortransmission data Data2, and a phase modulation unit 522 configured tooutput a phase-modulated drive signal X₂(t)=r₂∠θ₂ to the drive electrodeEd coupled thereto. In one embodiment, the drive circuits 52 arerespectively coupled to the drive electrodes Ed through, for example, aplurality of switching elements (not shown).

For example, FIG. 7A is a schematic diagram of the QPSK modulation. Theencoding unit 4221 encodes the transmission data as, for example, fourcodes 11, 01, 00 and 10, and the modulation unit 4222 outputs the drivesignal X₁(t)=r₁∠θ₁ with four phases 45°, 135°, 225° and 315°respectively according to the encoding of the encoding unit 4221, andthe drive signal X₁(t) is inputted to the drive electrodes Ed.

As mentioned above, the receiving electrodes Er of the touch panel 40are respectively output a detection signal y₁(t) according to thecoupling electric field Ec as well as the coupling electric fieldbetween drive electrodes and receiving electrodes therein. In the touchdetection mode, the detection signal y₁(t) is associated with the drivesignal inputted into the touch panel 40. In the near field communicationmode, the detection signal y₁(t) is associated with only the drivesignal inputted into the touch panel 50 or associated with both thedrive signals inputted into the touch panel 40 and the touch panel 50.The receiving electrodes Er of the touch panel 50 are respectivelyconfigured to output a detection signal y₂(t) according to the couplingelectric field Ec as well as the coupling electric field between driveelectrodes and receiving electrodes therein. Similarly, informationcontained in the detection signal y₂(t) is determined according to acurrent operating mode of the touch panel 50.

As mentioned above, the detection circuit 43 may be sequentially coupledto the receiving electrodes Er of the touch panel 40 (e.g. as shown inFIG. 5), and modulates the detection signal y₁(t) respectively with twosignals to generate two detection components I₁, Q₁ as shown in FIGS. 3Aand 3B. The detection circuit 53 may be sequentially coupled to thereceiving electrodes Er of the touch panel 50 (e.g. as shown in FIG. 5),and modulates the detection signal y₂(t) respectively with two signalsS₁, S₂ to generate two detection components I₁, Q₁. As mentioned above,the detection circuits 43, 53 may further include the integratorconfigured to integrate the detection signal y(t) and the ADC unitconfigured to perform the analog-to-digital conversion as shown in FIGS.3A and 3B.

The processing unit 44 is coupled to the detection circuit 43 andconfigured to obtain a norm of vector according to the two detectioncomponents I₁, Q₁ to accordingly identify a touch event, wherein asshown in FIG. 4 the processing unit 44 may calculate the norm of vector,which is compared with a threshold TH, by CORDIC. The processing unit 54is coupled to the detection circuit 53 and configured to obtain a normof vector according to the two detection components I₂, Q₂ toaccordingly identify a touch event and obtain a phase value according tothe two detection components I₂, Q₂ to accordingly decode transmissiondata Data1′, wherein the transmission data Data1′ may totally orpartially identical to the transmission data Data1 sent by the firstcapacitive touch device 400 depending on the bit error rate. In thisembodiment, the transmission data Data1′ is obtained by calculating anarctan(Q₂, I₂) of the two detection components I₂, Q₂ by a CORDIC 541 soas to obtain a phase value, and then decoding the phase value by adecoding unit 542. It is appreciated that the decoding unit 542 decodesthe phase value corresponding to the encoding of the encoding unit 4221

In addition, in this embodiment in order to decrease the bit error rate,the processing unit 54 may further include a performance circuit 55. Theperformance circuit 55 includes, for example, an error detectorconfigured to detect the bit error rate and a phase lock loop (PLL)configured to synchronize signals, track an input frequency, or generatea frequency that is a multiple of the input frequency. The phase lockloop includes, for example, a loop oscillator, a voltage controloscillator (VCO) or a numerical control oscillator (NCO), and the outputof the performance circuit 55 is feedback to multipliers 531, 531′ and551, wherein the multipliers 531 and 531′ are configured to modulate thedetection signal y₂(t) with two signals (e.g. S₁ and S₂ shown in FIG.7), and the multiplier 551 is configured to feedback the output of theperformance circuit 55 to the detection signal y₂(t), e.g. adjusting thegain thereof.

In addition, if the touch panel 40 is also served as the receiving endof a communication system, the processing unit 44 also obtains phasevalues according to the two detection components I₁, Q₁ to accordinglydecode transmission data Data2′, and performs identical processes andhas identical functions as the processing unit 54, e.g. furtherincluding a performance circuit and a decoding unit, but not limitedthereto.

It should be mentioned that the drive circuit 52 of the secondcapacitive touch device 500 in FIG. 7 may include both a drive unit 521and a phase modulation unit 522, or include the drive unit 521 withoutthe phase modulation unit 522 depending on the function thereof. Forexample, if the second capacitive touch device 500 is configured toreceive the near field communication data without sending the near fieldcommunication data, the drive circuit 52 may include only the drive unit521 configured to output the phase-fixed drive signal x(t). In addition,in FIG. 7 the detection circuit 43 and the processing unit 44 of thefirst capacitive touch device 400 may be identical to the detectioncircuit 53 and the processing unit 54 of the second capacitive touchdevice 500, and details of the detection circuit 43 and the processingunit 44 are not shown for simplification. In addition, in FIG. 7 theprocessing unit 44 of the first capacitive touch device 400 may notinclude the performance circuit and the decoding unit depending on thefunction thereof. For example, if the first capacitive touch device 400is configured to identify the touch event without performing the nearfield communication, only the CORDIC is included and the CORDIC isconfigured to calculate the norm of vector of the two detectioncomponents I₁, Q₁ but not calculate the phase value accordingly.

More specifically, in the first capacitive touch device 400 and thesecond capacitive touch device 500, when the function of transmittingthe near field transmission data is included, the transmitting endincludes the phase modulation unit, otherwise the phase modulation unitmay not be included; and when the function of receiving the near fieldtransmission data is included, the receiving end includes the decodingunit (further including the performance circuit in some embodiments) andis configured to calculate the norm of vector and the phase valueaccording to the two detection components, otherwise the receiving endmay not include the performance circuit and the decoding unit and isconfigured to calculate the norm of vector of the two detectioncomponents but not to calculate the phase value according to the twodetection components.

For example in one embodiment, the first capacitive touch device 400 isserved as a transmitting device of the near field communication and thesecond capacitive touch device 500 is served as a receiving device ofthe near field communication. When a distance between the firstcapacitive touch device 400 and the second capacitive touch device 500is larger than a near field communication distance Dc (e.g. 10 cm) asshown in FIG. 9, the second capacitive touch device 500 is operated in atouch detection mode and the drive circuit 52 outputs the phase-fixeddrive signal x(t). When the drive circuit 52 does not receive acommunication enabling signal, the phase-fixed drive signal x(t) iscontinuously outputted, wherein the communication enabling signal is forenabling the second capacitive touch device 500 to enter a near fieldcommunication mode from the touch detection mode.

In one embodiment, the second capacitive touch device 500 detects anaccess code successively or every a predetermined time interval in asynchronization process to accordingly identify whether to enter thenear field communication mode, wherein the access code includes, forexample, the synchronization word, compensation code and/or deviceaddress. In order to detect whether to enter the near fieldcommunication mode, the processing unit 54 may calculate the norm ofvector and the phase value according to an identical pair of the twodetection components I₂ and Q₂ as shown in the lower part of FIG. 10. Asmentioned above, as the phase variation in the detection signal does notinfluence the norm of vector of the two detection components I₂ and Q₂,the processing unit 54 may calculate both the norm of vector and thephase value according to the two detection components I₂ and Q₂ withinidentical time intervals (e.g. t_(touch)&t_(com) in FIG. 10). In anotherembodiment, the processing unit 54 may alternatively calculate the normof vector and the phase value according to different pairs of the twodetection components I₂ and Q₂ (e.g. t_(touch) and t_(com) in FIG. 10)as shown in the upper part of FIG. 10.

In the synchronization process, the processing unit 54 is configured tocompare a plurality of communication data with a predetermined codesequence (e.g. the access code) so as to confirm whether thesynchronization is accomplished, wherein the predetermined code sequenceincludes, for example, Barker codes which are configured to synchronizephases between the transmitting end and the receiving end, but notlimited thereto. The predetermined code sequence may also be othercoding used in conventional communication systems. In one embodiment,when the processing unit 54 identifies that a correlation between aplurality of phase values (or transmission data) and the predeterminedcode sequence exceeds a threshold, it means that the synchronization isaccomplished and the processing unit 54 controls the second capacitivetouch device 500 to enter the near field communication mode. In anotherembodiment, when the processing unit 54 identifies that a plurality ofphase values (or transmission data) matches a predetermined codesequence (e.g. the access code), it means that the synchronization isaccomplished and the processing unit 54 controls the second capacitivetouch device 500 to enter the near field communication mode. Forexample, when the near field communication mode is entered, theprocessing unit 54 outputs the communication enabling signal to thedrive circuit 52 and stops identifying the touch event but only decodesthe transmission data. When the drive circuit 52 receives thecommunication enabling signal, the drive signal x(t) is ceased.

In another embodiment, the communication enabling signal is outputtedaccording to a trigger signal of a predetermined application (APP) or apress signal of a button. For example, when an icon shown on a screen ofthe second capacitive touch device 500 is triggered or a button ispressed, the processing unit 54 receives the trigger signal or the presssignal and then outputs the communication enabling signal to the drivecircuit 52. Next, the processing unit 54 detects an access code within asynchronization time interval, and when the synchronization isaccomplished, the payload, i.e. the transmission data Data1, is receivedfrom the first capacitive touch device 400.

In this embodiment, as the first capacitive touch device 400 is servedas a transmitting end to communicate with an external electric field,the first capacitive touch device 400 is served as a capacitivecommunication device. The first capacitive touch device 400 includes atleast one drive electrode Ed configured to form the coupling electricfield Ec with the external electric field. The drive circuit 42 isconfigured to output a phase-modulated signal of the predetermined codesequence (i.e. the access code) to the at least one drive electrode Edof the touch panel 40 to communicate through the coupling electricelectrode Ec. For example, the first capacitive touch device 400 mayinclude only one drive electrode Ed to be served as a transmittingantenna so as to form one touch detection point.

In this embodiment, as the second capacitive touch device 500 is servedas a receiving end to communicate with an external electric field, thesecond capacitive touch device 500 is also served as a capacitivecommunication device. The second capacitive touch device 500 may includeat least one receiving electrode Er configured as a receiving antenna toform a coupling electric field Ec with the external electric field, andthe receiving electrode Er is configured to output a detection signaly₂(t) according to the coupling electric field Ec.

Referring to FIGS. 11A-11C, they are schematic diagrams of the inducedelectric field between a drive electrode Ed and a receiving electrodeEr. According to FIGS. 11A and 11B, when a finger approaches, theinduced electric field is weakened, i.e. E2<E1. According to FIGS. 11Aand 11C, when an external capacitive touch device 500 approaches, theinduced electric field is increased, i.e. E3>E1. Therefore, although inthe present disclosure the touch event and the transmission data may bedetected at the same time, the threshold TH to be compared with the normof vector may be different in the touch detection mode and the nearfield communication mode thereby increasing the accuracy of identifyingthe touch event. For example, in the near field communication mode, ahigher threshold may be used.

Referring to FIG. 12, it is a flow chart of a communication method of acommunication system according to one embodiment of the presentdisclosure, which includes the steps of: inputting a phase-modulateddrive signal to a touch sensing area of a first touch panel (Step S₆₁);detecting a coupling electric field with a touch sensing area of asecond touch panel to output a detection signal (Step S₆₂); inputting aphase-fixed drive signal to the touch sensing area of the second touchpanel (Step S₆₃); modulating the detection signal respectively with twosignals to generate two detection components (Step S₆₄); obtaining aphase value according to the two detection components to accordinglydecode transmission data from the first touch panel (Step S₆₅); andobtaining a norm of vector according to the two detection components toaccordingly identify a touch event of the second touch panel (Step S₆₆),wherein the Steps S₆₃ and S₆₆ may not be implemented according todifferent applications.

Referring to FIGS. 7, 9 and 12, details of this embodiment areillustrated hereinafter.

Step S₆₁: When a distance between a first touch panel (e.g. the touchpanel 40 herein) and a second touch panel (e.g. the touch panel 50herein) is smaller than a near field communication distance Dc, thefirst touch panel 40 enters a near field communication mode. Meanwhile,the drive circuit (e.g. the drive circuit 42 herein) of the firstcapacitive touch device 400 inputs the phase-modulated drive signalX₁(t)=r₁∠θ₁ to a touch sensing area 401 of the first touch panel 40. Forexample, the distance may be identified according to the increment ofthe electric field as shown in FIG. 11C.

Step S₆₂: As a distance between the first touch panel 40 and the secondtouch panel 50 is smaller than the near field communication distance Dc,a coupling electric field Ec is formed therebetween. A touch sensingarea 501 of the second touch panel 50 then outputs a detection signaly₂(t) according to the coupling electric field Ec.

Step S₆₃: If the second touch panel 50 does not detect the touch eventin the near field communication mode, this step may not be implemented.Otherwise, the drive circuit 52 of the second capacitive touch device500 outputs a phase-fixed drive signal x(t) to the touch sensing area501 of the second touch panel 50 such that the detection signal y₂(t)contains the output information of both the drive circuit 42 and thedrive circuit 52.

Step S₆₄: The detection circuit 53 of the second capacitive touch device500 modulates the detection signal y₂(t) respectively with two signals(e.g. S₁ and S₂ shown in FIG. 3A) to generate two detection componentsI₂ and Q₂.

Step S₆₅: The processing unit 54 of the second capacitive touch device500 obtains a phase value according to the two detection components I₂and Q₂ to accordingly decode transmission data Data1′ sent from thefirst touch panel 40.

Step S₆₆: If the second touch panel 50 does not detect the touch eventin the near field communication mode, this step may not be implemented.Otherwise, the processing unit 54 of the second capacitive touch device500 further obtains a norm of vector, which is then compared with atleast one threshold (e.g. as shown in FIG. 4), according to the twodetection components I₂ and Q₂ to accordingly identify a touch event ofthe second touch panel 400.

It should be mentioned that in this embodiment, the first touch panel 40may also be a receiving end and the second touch panel 50 may also be atransmitting end. It is appreciated that when both the first touch panel40 and the second touch panel 50 are used to send data, after thesynchronization the transmitting interval is further arranged, e.g.transmitting data alternatively.

Referring to FIGS. 13 and 14, FIG. 13 is a block diagram of a capacitivecommunication system according to an alternative embodiment of thepresent disclosure; and FIG. 14 is a schematic diagram of a capacitivecommunication system according to an alternative embodiment of thepresent disclosure. The capacitive communication system of thisembodiment includes an object 60 and a capacitive touch device, whereinthe second capacitive touch device 500 in FIGS. 7-9 is taken as anexample for illustrating the capacitive touch device herein.

As mentioned above, the second capacitive touch device 500 includes acapacitive touch panel 50 and a touch sensing area 501. Every element ofthe second capacitive touch device 500 has been illustrated above andthus details thereof are not described herein. The present embodiment isdifferent in that the capacitive touch device 500 includes a modulator522′ which is not limited to performing the phase modulation. Themodulator 522′ is possible to further perform the amplitude modulationand/or the frequency modulation.

The object 60 includes a plurality of induction conductors (e.g., 4induction conductors P1 to P4 are taken as an example herein) configuredto have different potential distributions at different time intervals bymodulating respective potentials on the induction conductors. Forexample in FIG. 15A, the induction conductors P1 to P4 have differentpotential distributions at times t₁ to t₄. FIG. 15A is a schematicdiagram of identification data according to an alternative embodiment ofthe present disclosure, wherein filled rectangles are referred to adigital value “1” and blank rectangles are referred to a digital value“0”, and vice versa. The material of the induction conductors P1 to P4does not have particular limitations as long as capacitance of thecapacitive touch panel 50 is changed when the induction conductors P1 toP4 are nearby.

The capacitive touch panel 50 includes a plurality of sensing electrodes(e.g., Ed and Er of FIG. 8) configured to form a coupling electric fieldEc with the induction conductors P1 to P4 (as shown in FIG. 14) so as todetect the different potential distributions at the different timeintervals (e.g., times t₁ to t₄ of FIG. 15A). When the differentpotential distributions match a predetermined agreement between thecapacitive touch panel 50 (or the capacitive touch device 500) and theobject 60, a near field communication between the capacitive touch panel50 and the object 60 is formed. In one embodiment, the near fieldcommunication is a Bluetooth communication, but not limited thereto.

Said predetermined agreement does not have particular limitations aslong as the object 60 and the capacitive touch device 500 arerecognizable. Accordingly, the predetermined agreement may be previouslyset before shipment or implemented by installing application software inthe capacitive touch device 500. In one embodiment, the inductionconductors P1 and/or P4 are used as the clock bit for sending clockdata, and the induction conductors P2 and P3 are used as data bits forsending transmission data Data1. For example, said predeterminedagreement is shown as potential distributions in FIG. 15A sequentiallydetected by sensing frames of the capacitive touch device 500 at timest₁ to t₄. More specifically, the potential at each time (e.g., t₁ to t₄)and the potential variation between each time (e.g., t₁ to t₄) of theinduction conductors P1 to P4 are detectable by the capacitive touchpanel 50.

In addition, for confirming a direction of the object 60 with respect tothe capacitive touch panel 50, one of the induction conductors P1 to P4is used as an orientation bit or positioning bit, e.g., one of the clockbit(s) is served as the orientation bit. Accordingly, a relativedirection of the object 60 with respect to the capacitive touch panel 50is recognizable so as to confirm a sequence of bits of the inductionconductors P2 and P3, e.g., P2 is prior to P3 herein.

The object 60 is, for example, an electronic lock, a mouse device, anearphone, a watch, a bracelet, a smart pen, a doll or an electronicmobile device having another capacitive touch panel. The inductionconductors P1 to P4 are arranged, for example, on an object surface 61of the object 60 to be easily detected by the capacitive touch panel 50.For example, when the object 60 is a mouse 60′ (referring to FIG. 16),the induction conductors P1 to P4 are arranged at a bottom surface ofthe mouse 60′, e.g., at four supporting protrusions at the bottomsurface (i.e., the object surface 61), but not limited thereto. It ispossible to dispose the induction conductors P1 to P4 inside the object60.

Accordingly, when the mouse 60′ is positioned on the capacitive touchpanel 50 of the capacitive touch device 500 (e.g., a notebook computeris taken as an example in FIG. 17), the capacitive touch device 500 isable to detect the approaching of the induction conductors P1 to P4,e.g., capacitance being changed. The capacitive touch device 500 is ableto confirm whether a near field communication mode is entered accordingto an arrangement characteristic of the induction conductors P1 to P4.

For example, the induction conductors P1 to P4 have the arrangementcharacteristic such as predetermined areas, a predetermined potentialdistribution and a predetermined arrangement, and said arrangementcharacteristic is previously stored in a memory of the capacitive touchdevice 500. When the capacitive touch device 500 confirms thepredetermined areas (e.g., respective area of each induction conductor),the predetermined potential distribution (e.g., potentials of everyinduction conductor at one time) and/or the predetermined arrangement(e.g., pitch and/or shape being formed), a near field communication modeis entered so as to detect the different potential distributions at thedifferent time intervals, e.g., a plurality of sensing elements 510(referring to FIG. 8) which sense the induction conductors P1 to P4indicating the matching with the predetermined areas, the predeterminedpotential distribution and/or the predetermined arrangement. Morespecifically, the capacitive touch device 500 is able to recognize arespective area, a respective potential or potential variation, anarrangement shape or pitch of the induction conductors P1 to P4according to a plurality of sensing elements 510 which sense theinduction conductors P1 to P4. When the arrangement characteristicmatches the pre-stored information in the capacitive touch device 500,the near field communication mode is entered.

In some embodiments, the arrangement characteristic is time-variant,e.g., the predetermined potential variation (i.e. potential variationpattern) within a predetermined period of one or several inductionconductors P1 to P4. More specifically, the arrangement characteristicmay be a combination of several characteristics so as to improve theidentification accuracy. For example, the predetermined areas, thepredetermined potential distribution and/or the predeterminedarrangement is used as the arrangement characteristic of a first stage,and then the predetermined potential variation of the one or severalinduction conductors P1 to P4 is used as the arrangement characteristicof a second stage.

When the predetermined potential variation is used as the arrangementcharacteristic, the capacitive touch device 500 preferably has abuffering time, which is longer than the predetermined period, inidentifying a touch, i.e. a touch event being confirmed occurring when aplurality of successive sensing frames detect the touch, and thecapacitance variation within the predetermined period not taken as atouch event.

Referring to FIGS. 13 and 14, it should be mentioned that although FIGS.13 and 14 show that the object 60 includes 4 induction conductors P1 toP4, they are only intended to illustrate but not to limit the presentdisclosure. It is possible that the object 60 includes at least oneinduction conductor (e.g., one or two induction conductors), but anumber of the induction conductors does not limited to that given in thepresent disclosure. In addition, every conductor P1 to P4 may havedifferent areas or shapes for being distinguished.

The object 60 further includes a controller 63, which is amicrocontroller (MCU) or an application specific integrated circuit(ASIC), coupled to the at least one induction conductor. The controller63 is used to modulate a potential of the at least one inductionconductor to be used as identification data, wherein the identificationdata is, for example, shown as potential distributions of the at leastone induction conductor (e.g., P1 to P4) at times t₁ to t₄ in thesynchronization pattern of FIG. 15A. The identification data is for thecapacitive touch device 500 to distinguish different objects. In otherwords, the capacitive touch device 500 stores therein (e.g., in amemory) the identification data associated with at least one object tobe compared with a detection result. The memory is volatile ornonvolatile without particular limitations.

The capacitive touch panel 50 includes at least one sensing electrode(e.g., Er shown in FIG. 8) and a processing unit 54. The at least onesensing electrode is used to form a coupling electric field Ec with theat least one induction conductor, wherein the sensing electrode is usedto output a detection signal y₂(t) corresponding to the identificationdata according to the coupling electric field Ec. The processing unit 54is, for example, a central processing unit (CPU) and used to identifywhether the object 60 is a specific object according to the detectionsignal y₂(t), wherein said specific object is an object which hasassociated and predetermined application software in the capacitivetouch device 500, and information of the specific object is pre-storedin the capacitive touch device 500.

In one embodiment, the controller 63 modulates a potential of the atleast one induction conductor with a fixed cycle to generate a potentialvariation. For example, in FIG. 15A, at times t₁ to t₄ a potentialvariation of the induction conductor P1 is shown to be 1→1→0→1, whereina time interval between t₁ and t₂, between t₂ and t₃ and between t₃ andt₄ are identical. Potential variations of the induction conductors P2 toP4 are also shown in FIG. 15A. FIG. 15A shows embodiments with two clockbits (upper half figure) and one clock bit (lower half figure), but notlimited thereto. The processing unit 54 of the capacitive touch device500 is used to obtain the potential variation according to the detectionsignal y₂(t), and identify whether the detected object is belong to aspecific object. For example, when the potential variation of theinduction conductor P1 (e.g., distinguished using the orientation bit)at successive time intervals matches 1→1→0→1, it is identified that theobject belongs to a predetermined specific object. Then, the capacitivetouch device 500 executes application software associated with thespecific object or performs other control(s) according to differentapplications.

Referring to FIG. 18, in some embodiments, the controller 63 controls,e.g., via a switching device 67, the induction conductors P1 to P4 to begrounded or floated to change the potential as “1” or “0”, but notlimited thereto. In other embodiments, the controller 63 is used tomodulate the amplitude, frequency and/or phase of the potential of theinduction conductors P1 to P4 without particular limitations as long as“1” and “0” are distinguishable.

When the object 60 includes a plurality of induction conductors (e.g.,two of P1 to P4), the controller 63 is used to respectively control arespective potential of every induction conductor. For example, in FIG.15A, the induction conductors P2 and P4 have different potentialvariations from time t₁ to t₄.

If the capacitive touch device 500 performs a near field communicationwith two induction conductors using only one sensing electrode (e.g.,one of Er in FIG. 8), the single sensing electrode is used to detect asum of potentials of the two induction conductors; i.e. the singlesensing electrode is used as a receiving antenna. In other words, thosestored in the capacitive touch device 500 are not the potentialvariation patterns of each induction conductor but are the variationpatterns of a sum of potentials. Similarly, when the object 60 includesmore than two induction conductors, the single sensing electrode is alsoused to detect a sum of potentials of the more than two inductionconductors.

If the capacitive touch panel 50 performs a near field communicationwith two induction conductors using a plurality of sensing electrodes(e.g. Er of FIG. 8), the sensing electrodes are used to detect arespective potential of each of the two induction conductors. In otherwords, the capacitive touch device 500 stores potential variationpatterns of each of the induction conductors, e.g., shown in FIG. 15A.Similarly, when the object 60 includes more than two inductionconductors, the respective potential of each of the more than twoinduction conductors is detectable.

As mentioned above, to eliminate the interference on detecting resultsdue to the phase shift caused by the capacitance on signal lines, thecapacitive touch device 500 further includes a detection circuit 53coupled to the sensing electrode. The detection circuit 53 modulates thedetection signal y₂(t) respectively with two signals S₁ and S₂ togenerate two detection components I₂ and Q₂. The processing unit 54obtains a norm of vector according to the two detection components I₂and Q₂, and compares a plurality of norm of vectors corresponding to theidentification data with a predetermined code thereby identifyingwhether the object 60 is a predetermined specific object. In otherwords, in this embodiment, in addition to identifying a touch eventaccording to the norm of vector (e.g., referring to FIG. 4), theprocessing unit 54 further identifies potential variation patterns(e.g., referring to FIG. 15A) of every induction conductor (e.g. P1 toP4) according to a plurality of norm of vectors.

The capacitive touch device 500 preferably has a mechanism to switchfrom a touch detection mode to a near field communication mode. Asmentioned above, the mechanism is set as the capacitive touch device 500identifying whether a button is pressed or whether the capacitance valueof the capacitive touch panel 50 is increased. In other embodiments, themechanism is set as the capacitive touch device 500 identifying anarrangement characteristic of the at least one induction conductors(e.g., P1 to P4). As mentioned above, when the capacitive touch device500 recognizes the predetermined area, the predetermined potentialdistribution and/or the predetermined arrangement, a near fieldcommunication is entered.

In one embodiment, when the near field communication is entered, theprocessing unit 54 is selected to stop identifying a touch eventaccording to the detection signal y₂(t).

In the near field communication mode, the processing unit 54 is furtherused to send a transmission start signal when the identification data(e.g., the synchronization pattern in FIG. 15A) matches a predeterminedcode. After receiving the transmission start signal, the object 60 sendstransmission data. For example, FIG. 15B shows embodiments of thetransmission data 11, 10, 00 and 01 (e.g., corresponding to times t₁′ tot₄′) with two clock bits and one clock bit, but not limited thereto. Inthis embodiment, the synchronization pattern in FIG. 15A is used asidentification data, whereas the data pattern in FIG. 15B is used as thetransmission data associated with an operation of the object 60.

The transmission data includes digital information of the object 60,e.g., electricity information, operating pattern information, timeinformation, music information, tag information or the like. Inaddition, the capacitive touch device 500 is selected to show thetransmission data on a screen.

In the near field communication mode, the processing unit 54 is furtherused to control the capacitive touch panel 50 to output a responsecommunication data via the coupling electric field Ec when theidentification data matches a predetermined core (e.g., thesynchronization pattern in FIG. 15A). For example, when the object 60 isan electronic mobile device including another capacitive touch panel(e.g., the first capacitive touch device 400 in FIGS. 7 to 8), thecapacitive touch device 500 uses the transmission data Data2 as theresponse transmission data, wherein the response transmission data isused to control, for example, the operation state of the object 60(e.g., ON/OFF, sleep mode). In addition, when the object 60 is the firstcapacitive touch device 400, the induction conductors are selected froma part of the drive electrodes Ed. For example, the induction conductorP1 in FIG. 15A is replaced by the first drive electrode Ed of FIG. 8,the induction conductor P2 is replaced by the third drive electrode Edof FIG. 8, the induction conductor P3 is replaced by the fifth driveelectrode Ed of FIG. 8 and so on. In other words, a shape of theinduction conductor is not limited to be a circle.

Preferably, a distance (or pitch) between the induction conductors is atleast larger than 12 mm, but not limited to. The distance is determinedaccording to a resolution of the capacitive touch panel 50.

The conventional Bluetooth pairing procedure between a master device anda slave device is complicated, e.g., requiring more than 6 stepsincluding respectively setting the master device and the slave device,and the pairing being accomplished within a predetermined time. Oneembodiment of the above capacitive communication system is applicable tosimplify the triggering procedure of the Bluetooth pairing.

Referring to FIG. 19, it is a block diagram of Bluetooth pairingaccording to an alternative embodiment of the present disclosure. Thisembodiment is adapted to a Bluetooth pairing procedure between a masterdevice 73 including a capacitive touch panel 733 and a slave device 71including at least one induction conductor 711.

In this embodiment, the slave device 71 is, for example, said object 60which includes at least one induction conductor 711 (e.g., inductionconductors P1 to P4), a controller 713 (e.g., controller 63) and areceiver 715. The object 60, the at least one induction conductor P1 toP4 and the controller 63 have been described above, and thus detailsthereof are not repeated herein. The receiver 715 is used to receivedevice information ID₂ (e.g., address information) from the masterdevice 73. The receiver 715 is, for example, an optical receiver (e.g.,photodiode), an audio receiver (e.g., microphone), a capacitive sensingelement (e.g., capacitive touch panel) or a magnetic sensing element(e.g., Hall sensor) according to different applications.

The master device 73 is, for example, said capacitive touch device 500which includes a central processing unit 731 (e.g., the processing unit54), a capacitive touch panel 733 (e.g., the capacitive touch panel 50),a transmitter 735 and a Bluetooth interface 737. The capacitive touchdevice 500 and the capacitive touch panel 50 thereof are describedabove, and thus details thereof are not repeated herein. The transmitter735 is used to output the device information ID₂ of the master device73. The transmitter 735 is, for example, a light emitter (e.g., lightemitting diode), a sound generator (e.g., speaker), a sensing electrode(e.g., Ed, Er of FIG. 8) or magnetic generating component (e.g., magnet)according to different applications. The Bluetooth interface 737 is usedto perform the Bluetooth pairing with the slave device 71. The centralprocessing unit 731 is electrically coupled to the capacitive touchpanel 733, the transmitter 735 and the Bluetooth interface 737, and usedto identify whether the slave device 71 is a predetermined specificobject, control the transmitter 735 to send the device information ID₂to the slave device 71, and control the Bluetooth interface 737 toperform the Bluetooth pairing.

Referring to FIG. 20, in one embodiment, the Bluetooth pairing methodincludes the steps of: detecting, by a capacitive touch panel, at leastone induction conductor (Step S81); identifying, by a master device, anarrangement characteristic of the at least one induction conductor whenthe capacitive touch panel senses the at least one induction conductor(Step S83); and performing a Bluetooth pairing procedure when the masterdevice identifies the arrangement characteristic matching apredetermined agreement (Step S85).

Step S81: As mentioned above, when the slave device 71 approaches thecapacitive touch panel 733, the at least one induction conductor 711causes the capacitance variation of the capacitive touch panel 733.Accordingly, the master device 73 is able to identify that the slavedevice 71 appears near the capacitive touch panel 733.

Step S83: When the master device 73 identifies that the capacitive touchpanel 733 senses the at least one induction conductor 711, the masterdevice 73 starts to identify an arrangement characteristic of the atleast one induction conductor 711.

In one embodiment, the slave device 71 includes a single inductionconductor 711, e.g., one of P1 to P4 shown in FIGS. 13-15A. Thearrangement characteristic includes at least one of an area, a potentialand a potential variation of the single induction conductor 711 (e.g.,P1), wherein the potential may cause the capacitance of the capacitivetouch panel 733 changing to a predetermined value, and the potentialvariation may be the potential variation 1→1→0→1 from time t₁ to t₄shown in FIG. 15A.

In one embodiment, the slave device 71 includes a plurality of inductionconductors 711, e.g., P1 to P4 shown in FIGS. 13-15A. The arrangementcharacteristic includes at least one of a pitch Dp (referring to FIG.13), an arrangement pattern (e.g., spatial positioning and shape), apotential distribution pattern and a potential variation pattern (e.g.,temporal potential variation), as shown in FIGS. 15A and 15B.

Step S85: When the master device 73 identifies that the arrangementcharacteristic matches a predetermined agreement between the masterdevice 73 and the slave device 71, a Bluetooth pairing procedure isdirectly performed, wherein said Bluetooth pairing procedure is known tothe art. The present disclosure is to simplify a triggering procedure ofthe Bluetooth pairing procedure. A user only needs to put the slavedevice 71 (e.g., object 60) having an identifiable agreement with themaster device 73 within a detectable range of the capacitive touch panel733, e.g., the near field communication distance Dc shown in FIG. 9, theBluetooth pairing procedure is accomplished easily.

Referring to FIG. 21, it is another flow chart of a Bluetooth pairingbetween a master device and a slave device, including the steps of:detecting, by a capacitive touch panel, at least one induction conductor(Step S81); identifying, by a master device, an arrangementcharacteristic of the at least one induction conductor when thecapacitive touch panel detects the at least one induction conductor(Step S83); sending device information to a slave device when the masterdevice identifies the arrangement characteristic matching apredetermined agreement (Step S851); and performing a Bluetooth pairingprocedure when the slave device receives the device information (StepS852).

The difference from FIG. 20 is that in FIG. 21 the slave device 71 doesnot enter a Bluetooth pairing mode before approaching the capacitivetouch panel 733 such that device information ID₂ (e.g., theidentification data) of the master device 73 has to be received from themaster device 73 in order to enter the Bluetooth pairing mode (StepS851) and then the Bluetooth pairing procedure can be accomplished (StepS852). The Steps S81 and S83 are identical to those of FIG. 20 and thusdetails thereof are not repeated herein.

More specifically, in the present disclosure a triggering procedure ofthe Bluetooth pairing has two ways.

In the first way, before the slave device 71 approaches the masterdevice 73, the slave device 71 has entered a Bluetooth pairing mode.Accordingly, when the master device 73 identifies that the arrangementcharacteristic of the induction conductor 711 of the slave device 71matches a predetermined agreement, a Bluetooth pairing procedure isdirectly performed (as shown in FIG. 20).

In the second way, before the slave device 71 approaches the masterdevice 73, the slave device 71 does not enter a Bluetooth pairing mode.Accordingly, when the master device 73 identifies that the arrangementcharacteristic of the induction conductor 711 of the slave device 71matches a predetermined agreement, the master device 73 firstly sendsdevice information ID₂ (e.g., address information) to the slave device71, and a Bluetooth pairing procedure is performed after the slavedevice 71 receives the device information ID₂. In this embodiment, themaster device 73 sends the device information ID₂ via, for example, thecapacitance sensing, light, sound, or magnetic induction. Morespecifically, the master device 73 and the slave device 71 further havea pair of components for transmitting the device information ID₂, e.g.,a speaker and microphone, a light source and light sensor, and magneticgenerator and Hall sensor. The near field communication is used tocommunicate device information (e.g., ID₁ and ID₂) of the object (e.g.,71) and the capacitive touch panel (e.g., 73) for a Bluetoothcommunication

In other embodiments, the slave device 71 also includes a capacitivetouch panel to provide the arrangement characteristic to the masterdevice 73 via the capacitive touch panel thereof. In this case, theslave device 71 does not include another induction conductors used forproviding the arrangement characteristic, e.g., the capacitive touchpanel being used as a signal source. The slave device 71 may provide thearrangement characteristic and encoding information to the master device73 via the capacitive touch panel thereof, and receive encodinginformation from the master device 73 via the capacitive touch panelthereof such that the two devices may link through the near fieldcommunication thereby realizing the out-of-band pairing.

It should be mentioned that although the above embodiments are describedby the mutual-capacitive touch panel, i.e. the drive electrode andreceiving electrode crossing to each other, and said sensing electrodeincluding the drive electrode and receiving electrode, but the presentdisclosure is not limited thereto. In other embodiment, the capacitivetouch panel is a self-capacitive touch panel, i.e. the drive electrodeand the receiving electrode being identical, and said sensing electrodebeing the drive electrode and receiving electrode.

As mentioned above, the conventional capacitive touch device may onlydetect an amplitude variation of the detection signal so as to identifywhether a touch event occurs. Therefore, the present disclosure furtherprovides a capacitive communication system (FIGS. 13 and 14) and aBluetooth pairing method (FIGS. 20-21) that may realize the objectidentification and data transmission by using a near fieldcommunication.

Although the disclosure has been explained in relation to its preferredembodiment, it is not used to limit the disclosure. It is to beunderstood that many other possible modifications and variations can bemade by those skilled in the art without departing from the spirit andscope of the disclosure as hereinafter claimed.

What is claimed is:
 1. A capacitive communication system, comprising: anobject, the object comprising: a plurality of induction conductors,wherein at least one of the plurality of induction conductors isconfigured to transmit clock data; and a controller coupled to theplurality of induction conductors and configured to modulate potentialsof the plurality of induction conductors to be configured asidentification data; and a capacitive touch panel, the capacitive touchpanel comprising: at least one sensing electrode configured to form acoupling electric field with the plurality of induction conductors,wherein the sensing electrode is configured to output a detection signalcorresponding to the identification data according to the couplingelectric field; and a processing unit configured to identify whether theobject is a specific object according to the detection signal, whereinone of the plurality of induction conductors is configured as apositioning bit configured to recognize a direction of the object withrespect to the capacitive touch panel.
 2. The capacitive communicationsystem as claimed in claim 1, wherein the capacitive touch panel furthercomprises: a detection circuit coupled to the sensing electrode andconfigured to modulate the detection signal respectively with twosignals to generate two detection components, wherein the processingunit is configured to obtain a norm of vector according to the twodetection components, and compare a plurality of norm of vectorscorresponding to the identification data with a predetermined code toidentify whether the object is the specific object.
 3. The capacitivecommunication system as claimed in claim 1, wherein the controller isconfigured to modulate the potentials of the plurality of inductionconductors with a fixed cycle to generate a potential variation, and theprocessing unit is configured to obtain the potential variationaccording to the detection signal, and identify whether the object isthe specific object according to the potential variation.
 4. Thecapacitive communication system as claimed in claim 1, wherein theobject comprises two induction conductors, and the controller isconfigured to respectively modulate the potential of each of the twoinduction conductors.
 5. The capacitive communication system as claimedin claim 4, wherein the sensing electrode is configured to detect a sumof potentials of the two induction conductors.
 6. The capacitivecommunication system as claimed in claim 4, wherein the capacitive touchpanel comprises a plurality of sensing electrodes configured to detect arespective potential of the two induction conductors.
 7. The capacitivecommunication system as claimed in claim 1, wherein the controller isconfigured to modulate at least one of an amplitude, a frequency and aphase of the potentials.
 8. The capacitive communication system asclaimed in claim 1, wherein the plurality of induction conductors has apredetermined area, a predetermined potential and a predeterminedarrangement, and the processing unit is further configured to: enter anear field communication mode when identifying at least one of thepredetermined area, the predetermined potential and the predeterminedarrangement.
 9. The capacitive communication system as claimed in claim8, wherein in the near field communication mode, the processing unit isfurther configured to output a transmission start signal when theidentification data matches a predetermined code, and the object isfurther configured to send transmission data after receiving thetransmission start signal.
 10. The capacitive communication system asclaimed in claim 8, wherein in the near field communication mode, theprocessing unit is further configured to control the capacitive touchpanel to output a response transmission data when the identificationdata matches a predetermined code.
 11. The capacitive communicationsystem as claimed in claim 8, wherein when the near field communicationmode is entered, the processing unit stops identifying a touch eventaccording to the detection signal.
 12. A capacitive communicationsystem, comprising: an object comprising a plurality of inductionconductors configured to have different potential distributions atdifferent time intervals by modulating respective potentials on theinduction conductors; and a capacitive touch panel comprising aplurality of sensing electrodes configured to form a coupling electricfield with the induction conductors to detect the different potentialdistributions at the different time intervals, wherein when thedifferent potential distributions match a predetermined agreement, anear field communication between the capacitive touch panel and theobject is formed, wherein the induction conductors have predeterminedareas, a predetermined potential distribution and a predeterminedarrangement, and the capacitive touch panel is further configured toenter a near field communication mode to detect the different potentialdistributions at the different time intervals when identifying at leastone of the predetermined areas, the predetermined potential distributionand the predetermined arrangement.
 13. The capacitive communicationsystem as claimed in claim 12, wherein the near field communication isused to communicate device information of the object and the capacitivetouch panel for a Bluetooth communication.